In the last 30 years, a cardiac foe that lurks in the bloodstream has seen its ranks swell to new heights.

No, not cholesterol. The proportion of Americans with high cholesterol has actually fallen, thanks largely to the emergence of a cholesterol-busting class of drugs called statins. One of those pharmaceuticals, Lipitor, has been the nation's best-selling drug several years running.

Triglycerides, however, are on the rise, according to a study presented by a Jacksonville-based health organization at the American Heart Association's annual conference Sunday.

Aout one out of three Americans have too many triglycerides in their blood, the National Lipid Association said in the report. That's a 10 percent increase from 1976 levels.

Blame the nation's worsening eating habits, said the study's author, Jerome Cohen, an internal medicine and cardiology professor at St. Louis University.

When we eat too much of the wrong foods and don't exercise enough, the lipids accumulate in the body and in the arteries. This is what leads over time to diseases like heart attack and stroke. And these are our No. 1 and No. 3 killers," Cohen said.

The three key lipids when it comes to cardiac health are LDL (aka "bad" cholesterol), HDL ("good" cholesterol) and triglycerides (fat found in blood).

From the labels on butter tubs to the drug commercials shown during breaks from football games, cholesterol has managed to elbow its way into the American consciousness. Triglycerides have a much lower profile.

"We haven't heard much about triglycerides in the past," Cohen said.

Scientists dispute whether high triglyceride levels alone trigger heart disease. But most agree that an abundance of triglycerides, defined as a score of 150 and above, tends to exist alongside worse conditions like diabetes, high blood pressure and obesity.

Cohen's study is based on an analysis of the National Health and Nutrition Examination Survey. The study was funded by the drugmaker Abbott Laboratories.

It also showed a doubling in the number of Americans with high triglyceride levels but normal cholesterol amounts.

Lori Alexander, a Jacksonville drug researcher, said she isn't surprised by the results.

"It's absolutely trending with our increase in obesity. Anytime you have an increase in weight, in general, you're going to have an increase in triglycerides," she said.